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Home >> Chevrolet >> 2020 >> Spark LS, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Data Communications >> Diagnostic Information and Procedures >> DTC U0077 >> Diagnostic Fault Information
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Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Chassis High Speed GMLAN Serial Data (+)
or High Speed GMLAN Serial Data (+) 2
U0077 U0077, U0100 - U02FF* U0077 -
Chassis High Speed GMLAN Serial Data (-)
or High Speed GMLAN Serial Data (-) 2
U0077 U0077, U0100 - U02FF* U0077 -
* An open in only one chassis high speed GMLAN serial data circuit may allow degraded communication between the devices. An open between the X84 Data Link Connector (DLC) and the K56 Serial Data Gateway Module will only affect the communication with the scan tool. The devices will still communicate.